A pi variable attenuator with wide attenuation dynamics, and relevant control circuit

(19)

(11)

EP 0 903 850 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	17.07.2002 Bulletin 2002/29

(43)	Date of publication A2:
	24.03.1999 Bulletin 1999/12

(21)	Application number: 98440210.7

(22)	Date of filing: 18.09.1998

(51)	International Patent Classification (IPC)⁷: H03H 7/25

(84)	Designated Contracting States:
	AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
	Designated Extension States:
	AL LT LV MK RO SI

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Priority:

19.09.1997 IT MI972122

(71)	Applicant: ALCATEL
	75008 Paris (FR)

(72)	Inventor:
	Mammarella, Carlos 20040 Capriano di Briosco (Milano) (IT)

(74)	Representative: Colombo, Stefano Paolo et al
	Alcatel, Intellectual Property Department, Vimercate, Via Trento, 30 20059 Vimercate (MI) 20059 Vimercate (MI) (IT)

(54)	A pi variable attenuator with wide attenuation dynamics, and relevant control circuit

(57) A π variable attenuator with wide attenuation dynamics comprising three PIN diodes, two (DP1, DP2) pertaining to the shunt arms of the attenuator and one (DS) to the series arm, wherein to obtain the wide attenuation dynamics through a suitable control circuit (ZB), the bias current (Is) of the series diode is made independent from the bias currents (lp1, lp2) of the parallel diodes.

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